The Case of the Misidentified Pump Switches

Technician working in well is electrocuted after making contact with live wire from mislabeled switch

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When a well-drilling company sent technicians out to a small horse farm to drill/equip two wells, the job at hand seemed nothing more than routine. The events that would transpire after they arrived on-site, however, were anything but typical.

The scene

The technician, who drilled wells for a living and installed the necessary pumping, was certified and licensed to hold this position.

The man was in the process of connecting power cables from the power panel to the pump. The electrical switch, which was marked with the identification to the first tile-covered well in which he was working 9 ft below the surface, was actually connected to a second well 30 ft away. Similarly, the switch that was supposed to control the second well was hooked up to control the first, ultimately turning the scenario into a case of misidentified pump switches.

The accident

When the technician went into the first well, he turned off the power labeled for the first well, not knowing that it actually controlled the second. Just by chance, the power to the first well was not energized when he flipped the switch. However, it came back on a few minutes later — when the second technician from the same well-drilling company (who had no idea the switches were not labeled correctly either) turned on the power for the switch labeled for the second well, restoring power to the first well where his colleague was in the middle of wiring the pump.

Once power to the first well was restored, the first technician was electrocuted by the 240V source. Although the accident produced a loud noise (based on evidence uncovered after the fact), the second technician did not hear it at the time. A few minutes after the incident, he unsuspectingly climbed out of the second well and saw what had happened to his friend and colleague. He immediately cut the power and called 911. Once on-site, medical personnel reported burns and abrasions over a large part of the victim’s body, especially on the left side. He was pronounced dead at the scene, and the cause of death listed in his autopsy was “cardiac arrhythmia as the result of electrocution.”

The lawsuit

My forensic engineering team was retained by the plaintiff (the accident victim’s widow), who sued the electrician originally hired by the well-drilling company to wire the wells. The defendant, an independent contractor who was licensed and insured as an electrician, had performed work for the company in the past on an as-needed basis.

Our inquiry was two-fold. First, we needed to establish whether or not the victim had followed proper safety protocols. Next, we had to estimate how much time it took for him to die. Per state law, if it was determined that his death was not “quick” (i.e., he suffered for some time), the technician’s widow would be allowed a higher compensation amount.

Investigation and analysis

After some initial probing, we confirmed that the electrician, who had finished electrifying the wells a day before the drillers arrived on-site, had obviously mislabeled the power switches.

In this case, it was specifically relevant to determine the extent of the victim’s suffering before death, because the plaintiff might be awarded further compensation. Unfortunately, this meant analyzing the stages of pain before death in great detail, including: (1) the victim’s inability to let go of the energized conductor; (2) involuntary muscular contractions; (3) painful shock; (4) electrical burning of the skin with no ventricular fibrillation (v-fib); and (5) cardiac arrhythmia leading to v-fib and death.

Although the technician was not a trained electrician, he had 45 years experience as a well driller/pump installer and was registered in the state to perform these tasks. Based on the evidence and investigation that followed the lawsuit, we determined he had done everything right.

After reconstructing the events that led up to the accident, our investigation showed that the technician was in the final stage of hooking up the pump’s power cables when the accident occurred. Although he had turned off the switch, he did not assume the power was off. Instead, he climbed into the well and used a standard multimeter in testing mode to check if the wires were energized, and they were not. Then — and only then — did he strip the cables in order to connect them to the pump. The victim had been touching the bare conductors sporadically for several minutes, giving him confidence that they were indeed de-energized. Unfortunately, only a few more minutes stood between him and avoiding the tragedy altogether. Based on the working conditions he had experienced up until the electrocution, we determined the victim had no reason to believe the power cables he was working on would suddenly become lethal.

Despite these facts, the defendant’s lawyers questioned whether the victim had followed best practices for electrical safety. Specifically, he was not wearing gloves, he did not have insulated tools (wire stripper/pliers), and he was not even wearing a shirt. However, in his defense, he did turn off the electricity, and he double checked it with a meter. In the end, it was determined that as someone not licensed as an electrician, he had done all that was expected of him to assure his safety.

Our results clearly showed negligence on the part of the electrician who had mislabeled the switches. Now it was time to figure out the most likely scenario in which the technician had died. Consider two extreme cases: (1) He died almost instantly (3 sec to 20 sec) from v-fib, or (2) he died in 3 min. from asphyxiation. These are the most common types of death from electricity for low-voltage work. (Note: This was relevant because a case for a larger settlement due to suffering could be made if asphyxiation or v-fib were determined to be the mode of death.) Based on the evidence, we concluded that both (1) and (2) had occurred. Cardiac arrhythmia, cited by the coroner as the cause of death, encompasses both (1) and (2).

Before he died, the technician, who was of medium build, was standing up in the well, which had a diameter of just under 2.5 ft. Even after he was found dead, the technician’s body was slouched in a relatively vertical position. Because the cables were stripped and ready for their connection to the pump, we surmised that the technician died by reaching out for one of the conductors with his right hand, which revealed a small burn. Electricity must have traveled into his right hand, but in order to reach ground, the current went to the left side of his body.

Considering the tight fit in the well, it was impossible for the technician to touch the energized conductor with his right hand without his left side being forced against the round wall of the well. There were many burns on his left side, including those on his thigh, chest, arm, and left side of his face. The fact that there was an electric burn on his face proved crucial to the second part of our investigation.

There were no burns on the technician’s feet. We measured the resistance at various points of the soles of his shoes to confirm that electricity did not exit via his feet. With 120VAC RMS applied, we measured approximately 5mA of electricity traveling through the entire area of the soles of his work boots. This value did not change later when we retested his shoes after dipping them in saltwater.

A current of 9mA to 30mA is generally strong enough to electrocute a man via asphyxiation. This value is greater than the “let-go” current maximum. It was our position that the technician suffered from a low level current that caused his muscles to convulse violently. This would have eventually led to asphyxiation, yet we were not convinced this theory would stand up. Although a sufficiently large current (approximately 100mA) could have caused v-fib, leading to death in 20 sec. or less, we estimated that the time for the technician to die was at least 1 min. or more.

Our conclusions were supported by the following four facts in this case:

1) The burning on his left side was spotty, supporting the theory that a low level current caused convulsions. But this was not conclusive — an argument could also be made that a large current caused v-fib almost immediately, and the spotty burn pattern was caused by the different resistances of the contact points of the technician’s body with the wall.

2) The burn on the left side of the technician’s face was conclusive proof that the electrocution started with asphyxia and convulsions. If v-fib had started first, then there would be very little chance of burning on the left side of the technician’s face, because he would be dead in about 3 sec. Electricity would pass from his right hand to the left side of his body that was already touching the well wall. Even after his death, the technician was found slumped over in a position such that his head was down and cradled by his chest. His face was not touching the well wall. Our conclusion was that a low level of electric current caused the technician to convulse violently. At some point, the left side of his face touched the well wall in a fit of convulsion. An electric burn was thus created on the left side of the face.

3) Suppose that there was no v-fib, and the technician was asphyxiated. This would have made our work easy, but the evidence disagreed. It takes approximately 3 min. for the average adult human to die in this fashion. Because the technician’s health was robust, it can be argued that death under these circumstances could have taken longer than 3 min., strengthening the case that the victim suffered for a long time before death. However, after more analysis, we ruled out this hypothesis. The coroner’s report listed the deceased as being without cyanosis. Cyan is a shade of the color blue. Blood is normally blue or purple in color. It only appears red when oxygen binds to the hemoglobin. A normally healthy man has more than 90% of his blood hemoglobin bound with an oxygen molecule. Therefore, his blood appears red. During the process of asphyxiation, the lungs are not able to process oxygen in the usual way, causing the blood to turn its normal color (blue) and turning the person’s skin a blue hue. Because the victim did not exhibit cyanosis, he could not have completed his death via asphyxiation alone.

4) For human skin, the time to cause a burn can be inferred from the degree of the burn. Although some of the technician’s burns were superficial (first degree), others were dark and deep (third degree). These latter burns took longer to form — up to a minute.

The verdict

In the end, the lawsuit was settled quickly and decisively. Based on our investigation, there was no doubt that the electrician who wired the switches was clearly at fault for mislabeling them. This negligence was handled first, resulting in the electrician’s insurance provider paying the technician’s wife just under $1 million for wrongful death.

Based on the extensive burns on the left side of the body caused by convulsions, especially the burn on the left side of his face as well as the depth of third-degree burns elsewhere on his body, we concluded that the technician was in pain for at least 1 min. before he died. For this suffering, his widow received further compensation of approximately $450,000.

Hmurcik is a consultant at Lawrence V. Hmurcik, LLC. He can be reached at hmurcik@bridgeport.edu. Patel is a Ph.D. candidate at the University of Bridgeport, Bridgeport, Conn. He can be reached at saroshp@bridgeport.edu.

Discuss this Article 2

Sure the electrician miss labeled the switches.
But what about personal responsibility!
But what about the Lock out Tag out Try out! It is a NFPA 70E requirement!
He also should have known that having both switches off makes it impossible to confirm that you have the correct circuit Locked out.
I was taught that when closing a circuit and there is someone working near to ask them to stand clear.
Then to recheck their circuit once your circuit is energized.

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